Currently, prior art image sensors reduce cross talk between photodiodes or photosensitive areas by forming local oxidation of silicon (generally referred to as LOCOS) between adjacent photodiodes. LOCOS are generally wide so that valuable surface area is consumed by the LOCOS.
Shallow trench isolation (STI) is generally narrower in width than LOCOS which reduces that amount of surface area consumed. However, forming a STI between photodiodes produces the drawback of undesirable defects, such as damage to the portion of the epitaxial layer in which the STI is formed.
Consequently, a need exists for having an image sensor with STI for consuming less surface area without the drawbacks of damaging the epitaxial layer and lowering saturation of the photodiode. The present invention provides this solution.